1. Technical Field of the Invention
The present invention relates to cellular communications systems and, in particular, to the detection of fraudulent mobile station use within a cellular communications system.
2. Description of Related Art
In existing cellular telephone networks, fraudulent users may attempt to place long distance telephone calls by causing the network to recognize the calls as being placed by a legitimate subscriber. This goal is accomplished by cloning the mobile station of a subscriber, including its electronic serial number (ESN) and mobile identification number (MIN). The cloned mobile station then appears to the network to be the subscriber's legitimate mobile station, thereby allowing the fraudulent user to freely place calls, and in particular place long distance telephone calls, and charge those calls to the subscription for the real mobile station. In most cases, the subscriber is not aware of the fraudulent use until after receiving an invoice from the cellular service provider for calling services. It is only then that the fraudulent use of a cellular subscription is detected. By that time, however, thousands of dollars of unrecoverable calling charges for long distance calls have been incurred, and the fraudulent user has often moved on to the cloning and fraudulent use of another mobile station.
There is a need then for a mechanism that allows for a more prompt detection of fraudulent use of a cellular communications system subscription.